Obesity rates in the United States continue to worsen. So, too, does economic inequality. Are these trends related?

After remaining essentially flat in the 1950s and 1960s, the prevalence of obesity doubled in adults and tripled in children between the 1970s and 2000. According to new data from the Centers for Disease Control, the epidemic shows no signs of abating. Nearly four out of 10 adults are obese; for children, it’s nearly two out of 10. Most 2-year-olds today will develop obesity by age 35, according to a recent projection from our colleagues at Harvard.

The obesity epidemic affects every region of the country and every demographic group. But rates have increased the fastest among low-income Americans and racial minorities, exacerbating pre-existing health disparities.

Weight-related complications like hypertension, fatty liver, orthopedic problems, sleep apnea and Type 2 diabetes are bad enough when they strike in middle age. But they have become relatively commonplace at pediatricians’ practices across the country. In adults, obesity substantially increases the risk for some of the most feared illnesses, like heart disease, cancer and Alzheimer’s. At all ages, obesity is associated with social isolation, depression and other major mental health problems.

This burden on our bodies — as well as the effects of poor diet and inadequate physical activity at any weight — contributed to declines in life expectancy in 2015 and 2016. County-level maps show striking correspondence between areas with the highest obesity rates and those with the greatest increases in mortality (located predominantly in the South and Midwest).

According to the American Diabetes Association, the annual cost of diabetes in 2017 was $327 billion, including $237 billion in direct medical expenditures and $90 billion in reduced worker productivity. (More than 90 percent of diabetes cases are Type 2, which is strongly associated with obesity.) The total impact of obesity and its related complications on the United States’ economic output has been estimated at between 4 and 8 percent of gross domestic product. Even on the lower end, that’s comparable to the 2018 defense budget ($643 billion) and Medicare ($588 billion).

This economic burden hits low-income and otherwise disadvantaged populations the hardest, exacerbating income and wealth inequality. With insulin now costing up to $900 a month, a diagnosis of diabetes can mean financial ruin for a low-wage worker, especially if it results in uncompensated sick days or underemployment. And as disposable income declines, so too does the ability to afford a nutritious diet, creating a vicious cycle of poverty and diet-related disease.

These long-term fiscal pressures lead political parties to fight ever more ferociously over shrinking resources. Simply put, the more the government must spend on health care and the more tax revenues it loses, the less there is for discretionary spending (such as education, highways, the environment and defense) and safety net services.

There are, of course, many causes of political conflict today. But our ability to negotiate differences within a large, diverse society will inevitably be undermined by rising economic pressures on families, communities and government and growing disparities in health and well-being.

With the couple hundred billion dollars of savings that could be achieved by rolling back obesity, Republicans could have tax cuts, Democrats could have increased social spending and the common ground for compromise would grow.

Seventy percent of American adults are at least overweight, and body weight is strongly influenced by biology; we can’t blame individuals and expect personal responsibility to solve the problem. Instead, we need the government to pass a suite of policy changes to encourage healthy diets.

Right now the government is doing the opposite. Farm policies have made low-nutritional commodities exceptionally cheap, providing the food industry with enormous incentive to market processed foods comprised mainly of refined grains and added sugars. In contrast, vegetables, whole fruits, legumes, nuts and high-quality proteins are much more expensive and, in “food deserts,” often unavailable. Processed foods are heavily advertised, even in educational materials directed at young children. And as cheap calories have flooded the environment, opportunities to burn off those calories at school, in recreation and through physically active modes of transportation have declined.

The broad outlines of a healthy diet are clear. A recent study in JAMA found that people can lose meaningful amounts of weight and lower their risk of heart disease by limiting sugar, refined grains and processed foods. Here are some steps that could move us from a disease-producing dietary environment to a health-promoting one:

First, establish a federal commission to coordinate obesity policy, which is now fragmented among numerous federal, state and local agencies. This commission would serve as a counterweight to the corrosive political influence and manipulative marketing practices of “Big Food” manufacturers.

Second, adequately fund obesity research into innovative approaches for prevention and treatment, beyond the conventional focus on eating less and moving more.

Fourth, prioritize the quality of the nutrition in the National School Lunch Program and Supplemental Nutrition Assistance Program. Despite some recent improvements in school lunches, too often, cafeterias still look like fast food courts. It wouldn’t cost that much to invest in kitchens and train cafeteria workers so that schools could produce tasty meals from scratch with fresh vegetables and fruits, beans, minimally processed grains and healthful proteins.

Fifth, ban junk food advertising to young children, as recommended by the American Academy of Pediatrics and practiced in some European countries. Research shows that children below the age of 8 years are cognitively and psychologically defenseless against the manipulation of advertisements.

These policies would help us reverse the obesity epidemic, improve the health and financial well-being of millions, decrease inequality, halt the decline in life expectancy — and even promote a modicum of political comity.

David S. Ludwig is a co-director of the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital and a professor of pediatrics at Harvard Medical School. Kenneth S. Rogoff, a former chief economist at the International Monetary Fund, is a professor of economics at Harvard.